One technique to facilitate location determination is based on use of signal parameters of a signal received at a device whose position/location is to be determined. For example, measurements such as round-trip time (RTT), received signal strength indicator (RSSI), etc., can be used to facilitate position determination through such techniques as, for example, RTT-fingerprinting, RSSI-fingerprinting, etc.
Signal information needed for position determination (including indoor positioning determination using signals transmitted by WiFi base stations) can generally be collected by anyone with access to the venue. This may be problematic for venue owners operating the signal-transmitting base stations, who could lose possible monetization benefits they could have received from providing position-determination services that are being diverted by 3rd party (e.g., other mapping/location-determination service providers).
Furthermore, future positioning systems will likely leverage on-phone sensor measurements (accelerometers, rate gyros, magnetometers and barometers) as well as WiFi signals. Beacon messages from APs might be leveraged to obtain position or speed-dependent measurements. For instance, the RSSI and the channel impulse response (CIR) as estimated by a receiver from the beacon messages are dependent on position of the receiver relative to an AP. Variations in the CIR and the RSSI (i.e., fast fading statistics) can be used to estimate a mobile's speed (or at the very least, a stopped state). Currently, it is difficult to prevent/inhibit anyone from leveraging these kinds of receive-only measurements for positioning purposes.